The UK can't unilaterally join the EU. Given how various government members openly insulted the EU since the 2016 referendum, I don't see a majority in the EU for letting the UK join again. Besides, ROI and Spain might veto that because of NI and Gibraltar, respectively.
Whether or not a UK membership application is accepted or rejected is entirely the prerogative of the European Union. However, that is the *end* of the process. We must focus on the *beginning* of the process. The process is not going to begin unless people stop voting for the 3 pro-Brexit parties
Why should the EU accept the UK as a member when the former could have the latter as a colony? Because that's what the planned agreement on food safety will lead to.
It is highly unlikely that the EU will ever have to consider a membership application from the UK. Scotland, Wales and England will each be submitting separate membership applications.
I don't think that the English colonies Scotland, Wales, and Northern Ireland will become independent any time soon.